Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already cover readOnly, idempotent, non-destructive and closed-world, so the safety profile is done. The description adds genuinely new behavior context: the return format is Markdown and the payload is roughly a third the size of the HTML page, which helps an agent reason about context budget.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two short sentences, front-loaded with what is returned and in what format, with the slug-source hint trailing. No filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter read with no output schema, the description covers format, size profile and slug sourcing, which is sufficient to call correctly. It does not mention behavior for a missing or unknown slug, a minor remaining gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100% and already documents the slug pattern with an example. The description adds value beyond the schema by telling the agent where to obtain valid slugs, which the schema cannot express.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('full text of one article as Markdown') plus the keying parameter (slug). The parenthetical pointing to list_articles distinguishes it cleanly from that sibling, which enumerates rather than returns content.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes the agent to list_articles as the source of valid slugs, which is a concrete alternative/precedence signal. It does not spell out when not to use it (e.g. for excerpts or search), so it stops short of full when/when-not coverage.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.